There exist known methods for producing three dimensional images in an electronic domain from solid physical objects. Typically, these methods involve some form of data acquisition of information relative to the exterior surfaces of the object, either by contact or non-contact means. The result is a computer generated image of the exterior surface of the object. For example, one such method involves physical contact coordinate measuring methods. This particular method can produce accurate physical part dimensions, but is deficient because it is time consuming to use because of the amount of data generated and because it cannot readily secure interior features of the object. Non-contact methods such as laser scanning are also capable of creating accurate part dimensions, but like the coordinate measuring methods are not readily capable of capturing internal part features. Interior features, such as surface geometries and structural elements cannot readily be captured by these methods and so they are of limited use.
There do exist methods and apparatus for capturing both internal and external features of a physical object. This is a desired and sought after ability both from the stand point of quality control of manufactured parts and because of the desire to be able to reverse engineer objects. Among the methods utilized for these ends are the non-destructive techniques of ultrasound imaging and computed tomography (CT). Ultrasound imaging is generally not accurate for reproducing physical measurements with the desired accuracy. While CT can produce modeling data of the desired accuracy, the equipment used to perform this type of operation or inspection is often quite expensive, with costs for the x-ray producing equipment, the housing for the equipment, the sensors for detecting the x-rays, and the computer resources necessary to operate the CT system often raising the cost to a figure in the one million dollar range. In addition, CT presents a radiation hazard and requires special facilities to use this equipment, which adds to the cost of their acquisition and use. Known methods of quality control and reverse engineering can also require substantial time investments in terms of human time and central processing unit or computer time. A need exists to reduce the time, cost, and repeatability of quality control sampling and to provide manufacturers to reliably and accurately reverse engineer an object.
The advent of the computer and computer aided design (CAD) and computer aided manufacture (CAM) has greatly assisted and expedited the work of the engineer and draftsman in designing, drawing, and manufacturing objects of all kinds. These computer aided engineering tools has made it possible to design a part and manufacture it without ever going through the prototype development stage. The electronic data representing the drawings of these parts are retained in some form of memory, thereby allowing their subsequent access by interested parties. Many parts currently manufactured and sold as well as entire products are made from engineering drawings that were created before the beginning of the CAD/CAM era. Some of these drawings have disappeared or been destroyed and there is a desire to bring these parts and products into the CAD environment.
It would be desirable to have an apparatus and process for taking an existing object and reproducing it in an electronic medium, thereby allowing pre-CAD/CAM era objects to be incorporated into the electronic environment, for providing a less costly alternative quality control inspection method than is presently available, for reducing manufacturing costs and speeding products to market, and for enabling an object to be accurately and quickly reverse engineered.